Recently, image forming devices such as printers are highly demanded to (1) show high fineness and high image quality, (2) achieve more energy saving than ever before, (3) increase the image forming speed, and (4) decrease the running cost. Based on this, the properties required in toners have been increasingly high and have become various, and toners have been developed from variety of viewpoints. Regarding the viewpoint of energy saving, there is a demand for developing a toner that is easily fixed to a transfer material such as paper at low temperature. At the same time, with an improvement in image resolution, there is a demand for controlling glossiness of images in order to improve the image quality to a level similar to those of photographs and printing. Furthermore, in a case of a color copier, there is a demand for a good color mixing property and broad color reproducibility.
PTL 1 discloses a toner that is excellent in mold releasability in fixing of a toner for low energy fixing and is inhibited from showing an offset phenomenon by using a resin having specific physical properties and a specific wax to control the properties of the binder resin and the wax. However, when image formation is repeated using the toner described in PTL 1, the wax contained in the toner causes another problem of contaminating the inside of image forming apparatuses. This is a marked tendency particularly in high-speed image formation.
Furthermore, PTL 2 discloses a toner that does not cause contamination of a heating roller in long-term use in an apparatus not having a heating roller-cleaning mechanism by simultaneously using three or more types of specific waxes. PTL 3 discloses a toner that prevents contamination of, in an image forming method by flash fixing, a flash lamp and a deodorizing filter due to volatilization/sublimation of low-molecular-weight components such as a wax by regulating physical properties of polyolefin in a black toner.
Furthermore, PTL 4 proposes a toner provided with an excellent fixing property by containing a wax having a low melting point and a sharp melting property, in which the content of n-paraffin is high. PTL 5 proposes a toner provided with excellent hot offset resistance by regulating the average number of carbon atoms of hydrocarbon components of a wax.